Pick out the incorrect statement.

Options

A. `MnO_(4)^(2-)` is quite strongly oxidizing and stable only in very strong alkalies. In dilute alkali, water or acidic solutions , it disproportionates.
B. In acidic solutions, `MnO_(4)^(-)` is reduced to `Mn ^(2+)` and thus, `KMnO_(4)` is widely used as oxidizing agent
C. `KMnO_(4)` does not act as oxidizing agent in alkaline medium
D. `KMnO_(4)` is manufactured by the fusion of pyrolusite ore with KOH in presence of air or `KNO_(3).` followed by electrolytic oxidation in alkaline solution.

Answer

C

Explanation

Alkaline `KMnO_(4)` also acts as oxidizing agent.
`MnO_(4)^(-) +2H_(2) O+3e^(-)to MnO_(2)+ 4OH^(-)`
a) `MnO_(4)^(2-)` disproportionate in water, dilute alkali or acidic solution.
`overset((+6))(MnO_(4)^(2-))+4H^(+)to overset((+7))(2MnO_(4)^(-))+overset((+4))(+MnO_(2))+2H_(2)O`
b) `MnO_(4)^(-)` is reduced to `Mn^(2+)` involbing a change of five electrons.
`MnO_(4)^(-)+8H^(+)+5e^(-)to Mn ^(2+) +4H_(2)O`
d) `MnO_(2) +2KOH +1/2O_(2) to K_(2)MnO_(4) +H_(2) O`
Anode : `MnO_(4)^(2-)overset("Alkaline")underset("Solution")toMnO_(4)^(-)+e^(-)`
Cathode : `2H^(+)+2e^(-) to H_(2)`